Watts abruptly soured the mood. The rioting, recalls Mr. McPherson, who was then special counsel at the White House, returned the focus to the daunting challenge ahead: eliminating poverty in the nation's black ghettos.

The recent Los Angeles riots have summoned historical comparisons with Watts and the state of society at the time. In many ways, the context of Watts was completely different: Society was infused with a sense of hope about improving the lot of blacks. A Democratic president was turning a strong commitment to civil rights into action, having initiated and signed the Economic Opportunity Act - a major step in his "war on poverty" - in 1964.

The American economy was healthy, and the industrial sector, which offered work to low-skilled laborers, was growing.

Yet civil rights advocates of that time, both from inside and outside the Johnson administration, report a sense of d vu as they consider the L.A. riots of 1992. Many of the concerns are elemental:

That the sight of blacks destroying their own community will extinguish white desire to help them; that whites will throw their political support more toward politicians promising "law and order" rather than to those advocating programs to address the underlying problems; and that any responses to the rioting not be seen as "rewarding" the rioters.

In the White House debates after Watts, says McPherson, now a Washington lawyer, "the most common question was, are we rewarding the rioters?" But in his memoir, "A Political Education," from which he quotes liberally in an interview, McPherson calls that concern a "hollow issue."

"In the first place," he writes, "we will help to feed, heal, and house everyone who needs it, regardless of his moral position during the riots; in the second place, we don't have enough money to 'reward' anybody, if 'reward' means the massive rebuilding of slum areas. We didn't have it before the riots and we don't now."

For those already committed to the "war on poverty," Watts only heightened resolve. Roger Wilkins, who was assistant director of the US Community Relations Service in 1965, was sent by President Johnson to Watts after the riots to assess the situation.

"I suppose we learned some things" about how to carry out Johnson's Great Society plan, recalls Mr. Wilkins, now a history professor at George Mason University. "The poverty program was just fledgling when the riots started and people were walking around with community-action how-to booklets, but nobody knew how to put it together."

Even though there had been a cycle of riots in 1964, it was Watts that shocked the nation, Wilkins says. "The popular recollection was that Watts was first, so people said, 'We have to get a poverty program.' It speeded up local action all over the country."

Until that point, he says, a lot of people did not understand that the focus of poverty programs until then had been on the South.

"A lot of Northern whites thought [poverty] was just in the South. We said, 'Hey, it's a big problem in the North, too.' We made the argument and made the argument and made the argument - inside the government and to mayors around the country - just as many have been arguing this year that urban policy needs to be in the forefront of people's minds and in the campaign," Wilkins says. "As in 1965, the riots made our point for us."

McPherson is quicker to recognize the down side of rioting on white public opinion. In his book, he writes of the "liberal consensus" that had been formed around the need to remove the "obvious and obnoxious restrictions" that hindered blacks from voting, employment, and many everyday activities.

But having achieved that, the government faced the tougher challenge of building a new consensus around the need to address a situation in which there was no obvious villain - a situation of black men who appeared to choose unemployment, women who "chose" welfare, and young people who chose heroin.

"The riots in Watts and Newark and Detroit [in 1967], and the movie-gangster rhetoric of Rap Brown and Stokely Carmichael, strained the patience of the 'permissive' whites; depressed the responsible blacks; and disorganized white liberals," McPherson writes. "A few of the latter excused the riots as inevitable and even justifiable. Nothing could have been better calculated to undermine the consensus."

Today, McPherson sees a dearth of black civil-rights leaders able to help build a new consensus for the urban poor, with the exception of Jesse Jackson.

Furthermore, the black community of today is fractionalized, he says. In the early 1960s, all blacks - professionals and poor - were hindered by discriminatory laws and practices. Now, with many of the overt hindrances gone, blacks have had a harder time holding their cause together.

But the key to building a consensus in 1992, McPherson says, is the white middle class, which forms the bulk of the electorate. For some, he says, the L.A. riots will confirm the view that the poverty programs and civil rights act were a waste and were used to lash back at whites. For liberals, the rioting confirms that more needs to be done.

"That leaves a huge group in the middle," McPherson says. "In one sense, they are much more accustomed to working with and being with blacks. But they are dubious about federal efforts to redistribute income and about affirmative action and busing. I don't know where they are."

Looking to the future, Wilkins scoffs at the notion of convening yet another commission to examine the L.A. riots and America's urban plight. The McCone Commission report, issued in response to Watts, produced some results - including the building of a hospital and community center - but other key aspects went unimplemented, such as a call for police reform.

Wilkins suggests the White House convene a conference on civil rights and call in people from all over the country - businessmen, local officials, and educators. The task at hand is too big for government alone to handle, he says.